Ceramic capacitor

ABSTRACT

A ceramic capacitor having an improved electrode soldering performance, little or no diffusion of solder even in the case of being used under a high temperature environment and a reduced characteristic deterioration is provided. The dry plating electrodes have a three-layer structure. First layers of the electrodes are respectively provided on both surfaces of a ceramic element assembly and made of any one or more of Cu, Ni--Cu alloy and Zn. Second layers of the electrodes are respectively provided on the surfaces of the first layers and made of a material different from the material of the first layers and any one or more of Cr, Ni--Cr alloy, Fe--Cr alloy, Co--Cr alloy, Ti, Zn, Al, W, V and Mo. Third layers of the electrodes are respectively provided on the surfaces of the second layers and made of any one or more of Cu, Ni--Cu alloy, Ag and Au.

BACKGROUND OF THE INVENTION

The present invention relates to a ceramic capacitor and particularlyrelates to a plate like ceramic capacitor which is used in a hightemperature environment.

Generally, the ceramic capacitor of this type is structured such thatelectrodes are provided on both surfaces of the plate like ceramicelement assembly, and further, a lead terminal is soldered to each ofthe electrodes. Then, as a conventional electrode, a baked coatedelectrode or a wet plated electrode made of Ag, Cu or the like, which isa metal easily soldered, is applied or it has been considered to form abaked coated electrode or a wet plated electrode made of Ni, Zn or thelike, which is a metal in which the Sn contained in the solder is hardlydiffused, is applied.

When the ceramic capacitor having the baked coated electrode or the wetplated electrode made of Ag, Cu or the like is used in a hightemperature environment (for example, about 150° C.), the Sn containedin the solder used for bonding the lead terminal diffuses into theelectrode so that the bonding strength between the electrode and theceramic deteriorates. Accordingly, there is a risk of problems such asthe dielectric loss of the ceramic capacitor being increased, and coronadischarge produced in the gap between the electrode and the ceramic willbreak the ceramic capacitor.

In the case of the ceramic capacitor having the coated baked electrodeor the wet plated electrode made of Ni, Zn and the like, since Sncontained in the solder is hardly discharged, the above troubles do notoccur.

However, there occurs another problem such that the soldering operationof the electrode is deteriorated. Accordingly, it becomes necessary touse a chlorine flux which has a problem in reliably bonding the leadterminal and to provide another electrode for mounting the lead terminalon the electrode made of Ni, Zn or the like.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a ceramic capacitorhaving an improved performance when soldering an electrode, and nodiffusion of solder even in the case of being used in a high temperatureenvironment and reduced characteristic deterioration.

In order to achieve the above object, in accordance with the presentinvention, there is provided a ceramic capacitor comprising:

(a) a ceramic element assembly and a dry plated electrode provided on asurface of the ceramic element assembly; and

(b) the dry plated electrode having a first layer made of any one ormore of Cu, Ni--Cu alloy and Zn, a second layer provided on a surface ofthe first layer and of a material different from the material of thefirst layer and is any one or more of Cr, Ni--Cr alloy, Fe--Cr alloy,Co--Cr alloy, Ti, Zn, Al, W, V and Mo, and a third layer provided on asurface of the second layer and made of any one or more of Cu, Ni--Cualloy, Ag and Au. Further, it is preferable that the thickness of thefirst layer is about 500 angstroms or more, the thickness of the secondlayer is about 100 angstroms or more and the thickness of the thirdlayer is about 500 angstroms or more.

Due to the above structure, the first layer secures a suitable strongbonding between the ceramic element assembly and the electrode. Thesecond layer prevents diffusion of the solder (particularly, of Sncontained in the solder) from developing at the interface between theceramic element assembly and the electrode. Further, the third layerimproves the operability of the soldering.

Other features and advantages of the present invention will becomeapparent from the following description of the invention which refers tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross sectional view which shows an embodiment of a ceramiccapacitor in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a ceramic capacitor in accordance with the presentinvention will be explained below with reference to the accompanyingdrawing.

As shown in FIG. 1, a ceramic capacitor is provided with a ceramicelement assembly 1, electrodes 5a and 5b respectively formed on bothsurfaces of the ceramic element assembly, and lead terminals 6a and 6brespectively bonded to the electrodes 5a and 5b by solders 9a and 9b.The ceramic element assembly 1 is made of, for example, a ceramicdielectric of the BaTiO₃ system, SrTiO₃ system and TiO₂ system and thelike.

The electrodes 5a and 5b are formed on both surfaces of the ceramicelement assembly by a dry plating method after the ceramic elementassembly 1 is heated to a predetermined temperature. The heatingtemperature of the ceramic element assembly 1 is not critical but it ispreferable to set the temperature to about 150° C. or less so as todecrease the residual stress within the ceramic element assembly 1. Thedry plating method includes, for example, the sputtering method,depositing method, thermal spraying method, ion plating method and thelike. The dry plated electrodes 5a and 5b have a three-layerconstruction.

First layers 2a and 2b of the electrodes 5a and 5b are respectivelyprovided on both surfaces of the ceramic element assembly 1 and are madeof any one or more of Cu, Ni--Cu alloy and Zn. These metals or alloysare materials capable of obtaining a suitable bonding power with respectto the ceramic and the bonding power is considered to be obtained by asuitable bonding with oxygen within the ceramic. Accordingly, a suitablebonding strength can be secured between the ceramic element assembly 1and the electrodes 5a and 5b. On the contrary, if the bonding betweenthe metal (or the alloy) and the oxygen within the ceramic is too weak,the bonding strength between the ceramic element assembly and theelectrodes is insufficient, and inversely if the bonding is too strong,the characteristic is deteriorated due to reduction of the ceramicelement assembly.

Second layers 3a and 3b of the electrodes 5a and 5b are respectivelyprovided on the surfaces of the first layers 2a and 2b, and are made ofa material which is different from the material used for the first layer2a and 2b and comprises any one or more of Cr, Ni--Cr alloy, Fe--Cralloy, Co--Cr alloy, Ti, Zn, Al, W, V and Mo.

These metals or alloys materials into which Sn and Pb hardly diffuse sothat the diffusion of the solders 9a and 9b (particularly, of Sncontained in the solders 9a and 9b) does not extend to the interfacebetween the ceramic element assembly 1 and the electrode 5a and theinterface between the ceramic element assembly 1 and the electrode 5b.Accordingly, the bonding strength between the electrodes 5a and 5b andthe ceramic element assembly 1 is not deteriorated so that there doesnot occur the problems such that the dielectric loss of the ceramiccapacitor is increased, or that the ceramic capacitor is broken due tocorona discharge in the gap produced between the electrodes and theceramic element assembly.

Third layers 4a and 4b of the electrodes 5a and 5b are respectivelyprovided on the surfaces of the second layers 3a and 3b, and are made ofany one or more of Cu, Ni--Cu alloy, Ag and Au. These metals or alloysare materials having an improved wetting property vis-a-vis the solderso that the lead terminals 6a and 6b can be bonded to the electrodes 5aand 5b with high reliability.

Further, the thickness of the first layers 2a and 2b is set to about 500angstroms or more, the thickness of the second layers 3a and 3b is setto about 100 angstroms or more and the thickness of the third layers 4aand 4b is set to about 500 angstroms or more. This is because if thethickness is less than the above value, there is a risk that the aboveoperation and effect of the respective layers 2a to 4b will beinsufficiently obtained. The ceramic capacitor obtained by the abovemanner has an improved electrode 5a and 5b soldering performance, areduced diffusion developing characteristic of the solder even if theceramic capacitor is used under a high temperature environment, and areduced performance deterioration.

Further, the ceramic capacitor in accordance with the present inventionis not limited to the above embodiment and can be variously modifiedwithin the scope of the invention. Particularly, the shape of theceramic element assembly, the shape of the electrodes and the like areoptional so that various kinds of shapes such as a circular shape, anoval shape, a rectangular shape and the like can be selected incorrespondence to the specification.

Next, experimental results performed by the inventors of the presentinvention will be described below with reference to FIG. 1. A ceramiccapacitor sample for the experimentation is manufactured in thefollowing manner. After heating a disc like ceramic element assembly 1of BaTiO₃ system ceramic having a diameter of 13 mm and a thickness of0.5 mm to a temperature of 150° C. or less under a vacuum of 10⁻⁴ Torr,a metal or alloy selected among Cu, Ni--Cu alloy and Zn is sputtered tothe upper and lower surfaces of the ceramic element assembly 1, therebyrespectively forming the first layers 2a and 2b having a thickness of atleast 500 angstroms.

Next, a metal or alloy selected among Cr, Ni--Cr alloy, Fe--Cr alloy,Co--Cr alloy, Ti, Zn, Al, W, V and Mo is sputtered, thereby respectivelyforming the second layers 3a and 3b having a thickness of at least 100angstroms on the surfaces of the first layers 2a and 2b. Further, ametal or alloy selected among Cu, Ni--Cu alloy, Ag and Au is sputtered,thereby forming the third layers 4a and 4b having a thickness of atleast 500 angstroms on the surfaces of the second layers 3a and 3b.

As mentioned above, after the electrodes 5a and 5b are respectivelyformed on both surfaces of the ceramic element assembly 1, the leadterminals 6a and 6b made of a soldered annealed copper wire and having adiameter of 0.6 mm are respectively bonded to the electrodes 5a and 5bby solders 9a and 9b, and the wetting property of the solder thereof hasbeen observed. Further, after keeping the ceramic capacitor sample at atemperature of 125° C. for 1000 hours, electric characteristics such asdielectric constant ε, dielectric loss and insulation resistance havebeen measured. The measured results shown in tables 1--1 to 1-11 havebeen obtained. The wetting property of the solder in the tables isdetermined such as to be good if the contact angle between theelectrodes 5a and 5b and the solders 9a and 9b is less than 90 degrees,and to be bad if the contact angle is equal to or more than 90 degrees.

                  TABLE 1-1                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Cu    Cr      Cu      Good   8200  0.51   80000                               Cu    Cr      Ni--Cu  Good   8200  0.51   80000                                             (70:30)                                                         Cu    Cr      Ni--Cu  Good   8200  0.51   80000                                             (10:90)                                                         Cu    Cr      Ag      Good   8200  0.51   80000                               Cu    Cr      Au      Good   8200  0.51   80000                               Cu    Ni--Cr  Cu      Good   8200  0.51   80000                                     (90:10)                                                                 Cu    Ni--Cr  Ni--Cu  Good   8200  0.51   80000                                     (90:10) (70:30)                                                         Cu    Ni--Cr  Ni--Cu  Good   8200  0.51   80000                                     (90:10) (10:90)                                                         Cu    Ni--Cr  Ag      Good   8200  0.51   80000                                     (90:10)                                                                 Cu    Ni--Cr  Au      Good   8200  0.51   80000                                     (90:10)                                                                 Cu    Ni--Cr  Cu      Good   8200  0.51   80000                                     (20:80)                                                                 Cu    Ni--Cr  Ni--Cu  Good   8200  0.51   80000                                     (20:80) (70:30)                                                         Cu    Ni--Cr  Ni--Cu  Good   8200  0.51   80000                                     (20:80) (10:90)                                                         Cu    Ni--Cr  Ag      Good   8200  0.51   80000                                     (20:80)                                                                 Cu    Ni--Cr  Au      Good   8200  0.51   80000                                     (20:80)                                                                 Cu    Ni--Cr  Cu      Good   8200  0.51   80000                                     (83:17)                                                                 Cu    Ni--Cr  Ni--Cu  Good   8200  0.51   80000                                     (83:17) (70:30)                                                         Cu    Fe--Cr  Ni--Cu  Good   8200  0.51   80000                                     (83:17) (10:90)                                                         Cu    Fe--Cr  Ag      Good   8200  0.51   80000                                     (83:17)                                                                 Cu    Fe--Cr  Au      Good   8200  0.51   80000                                     (83:17)                                                                 ______________________________________                                    

                  TABLE 1-2                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Cu    Co--Cr  Cu      Good   8200  0.51   80000                                     (50:50)                                                                 Cu    Co--Cr  Ni--Cu  Good   8200  0.51   80000                                     (50:50) (70:30)                                                         Cu    Co--Cr  Ni--Cu  Good   8200  0.51   80000                                     (50:50) (10:90)                                                         Cu    Co--Cr  Ag      Good   8200  0.51   80000                                     (50:50)                                                                 Cu    Co--Cr  Au      Good   8200  0.51   80000                                     (50:50)                                                                 Cu    Ti      Cu      Good   8200  0.56   80000                               Cu    Ti      Ni--Cu  Good   8200  0.56   80000                                             (70:30)                                                         Cu    Ti      Ni--Cu  Good   8200  0.56   80000                                             (10:90)                                                         Cu    Ti      Ag      Good   8200  0.56   80000                               Cu    Ti      Au      Good   8200  0.56   80000                               Cu    Zn      Cu      Good   8200  0.62   80000                               Cu    Zn      Ni--Cu  Good   8200  0.62   80000                                             (70:30)                                                         Cu    Zn      Ni--Cu  Good   8200  0.62   80000                                             (10:90)                                                         Cu    Zn      Ag      Good   8200  0.62   80000                               Cu    Zn      Au      Good   8200  0.62   80000                               Cu    Al      Cu      Good   8200  0.60   80000                               Cu    Al      Ni--Cu  Good   8200  0.60   80000                                             (70:30)                                                         Cu    Al      Ni--Cu  Good   8200  0.60   80000                                             (10:90)                                                         Cu    Al      Ag      Good   8200  0.60   80000                               Cu    Al      Au      Good   8200  0.60   80000                               Cu    W       Cu      Good   8200  0.58   80000                               Cu    W       Ni--Cu  Good   8200  0.58   80000                                             (70:30)                                                         Cu    W       Ni--Cu  Good   8200  0.58   80000                                             (10:90)                                                         Cu    W       Ag      Good   8200  0.58   80000                               Cu    W       Au      Good   8200  0.58   80000                               ______________________________________                                    

                  TABLE 1-3                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Cu    V       Cu      Good   8200  0.58   80000                               Cu    V       Ni--Cu  Good   8200  0.58   80000                                             (70:30)                                                         Cu    V       Ni-Cu   Good   8200  0.58   80000                                             (10:90)                                                         Cu    V       Ag      Good   8200  0.58   80000                               Cu    V       Au      Good   8200  0.58   80000                               Cu    Mo      Cu      Good   8200  0.58   80000                               Cu    Mo      Ni--Cu  Good   8200  0.58   80000                                             (70:30)                                                         Cu    Mo      Ni--Cu  Good   8200  0.58   80000                                             (10:90)                                                         Cu    Mo      Ag      Good   8200  0.58   80000                               Cu    Mo      Au      Good   8200  0.58   80000                               Ni--Cu                                                                              Cr      Cu      Good   8300  0.48   60000                               (70:30)                                                                       Ni--Cu                                                                              Cr      Ni--Cu  Good   8300  0.48   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              Cr      Ni--Cu  Good   8300  0.48   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              Cr      Ag      Good   8300  0.48   60000                               (70:30)                                                                       Ni--Cu                                                                              Cr      Au      Good   8300  0.48   60000                               (70:30)                                                                       Ni--Cu                                                                              Ni--Cr  Cu      Good   8300  0.48   60000                               (70:30)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8300  0.48   60000                               (70:30)                                                                             (90:10) (70:30)                                                         Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8300  0.48   60000                               (70:30)                                                                             (90:10) (10:90)                                                         Ni--Cu                                                                              Ni--Cr  Ag      Good   8300  0.48   60000                               (70:30)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Au      Good   8300  0.48   60000                               (70:30)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Cu      Good   8300  0.48   60000                               (70:30)                                                                             (20:80)                                                                 ______________________________________                                    

                  TABLE 1-4                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8200  0.48   60000                               (70:30)                                                                             (20:80) (10:80)                                                         Ni--Cu                                                                              Ni--Cr  Ag      Good   8200  0.48   60000                               (70:30)                                                                             (20:80)                                                                 Ni--Cu                                                                              Ni--Cr  Au      Good   8200  0.48   60000                               (70:30)                                                                             (20:80)                                                                 Ni--Cu                                                                              Fe--Cr  Cu      Good   8200  0.48   60000                               (70:30)                                                                             (83:17)                                                                 Ni--Cu                                                                              Fe--Cr  Ni--Cu  Good   8200  0.48   60000                               (70:30)                                                                             (83:17) (70:30)                                                         Ni--Cu                                                                              Fe--Cr  Ni--Cu  Good   8200  0.48   60000                               (70:30)                                                                             (83:17) (10:90)                                                         Ni--Cu                                                                              Fe--Cr  Ag      Good   8200  0.48   60000                               (70:30)                                                                             (83:17)                                                                 Ni--Cu                                                                              Fe--Cr  Au      Good   8200  0.48   60000                               (70:30)                                                                             (83:17)                                                                 Ni--Cu                                                                              Co--Cr  Cu      Good   8200  0.48   60000                               (70:30)                                                                             (50:50)                                                                 Ni--Cu                                                                              Co--Cr  Ni--Cu  Good   8200  0.48   60000                               (70:30)                                                                             (50:50) (70:30)                                                         Ni--Cu                                                                              Co--Cr  Ni--Cu  Good   8300  0.48   60000                               (70:30)                                                                             (50:50) (10:90)                                                         Ni--Cu                                                                              Co--Cr  Ag      Good   8300  0.48   60000                               (70:30)                                                                             (50:50)                                                                 Ni--Cu                                                                              Co--Cr  Au      Good   8300  0.48   60000                               (70:30)                                                                             (50:50)                                                                 Ni--Cu                                                                              Ti      Cu      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              Ti      Ni--Cu  Good   8300  0.53   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              Ti      Ni--Cu  Good   8300  0.53   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              Ti      Ag      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              Ti      Au      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              Zn      Cu      Good   8300  0.55   60000                               (70:30)                                                                       ______________________________________                                    

                  TABLE 1-5                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Zn      Ni--Cu  Good   8300  0.55   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              Zn      Ni--Cu  Good   8300  0.55   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              Zn      Ag      Good   8300  0.55   60000                               (70:30)                                                                       Ni--Cu                                                                              Zn      Au      Good   8300  0.55   60000                               (70:30)                                                                       Ni--Cu                                                                              Al      Cu      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              Al      Ni--Cu  Good   8300  0.53   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              Al      Ni--Cu  Good   8300  0.53   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              Al      Ag      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              Al      Au      Good   8300  0.53   60000                               (70:30)                                                                       Ni--Cu                                                                              W       Cu      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              W       Ni--Cu  Good   8300  0.51   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              W       Ni--Cu  Good   8300  0.51   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              W       Ag      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              W       Au      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              V       Cu      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              V       Ni--Cu  Good   8300  0.51   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              V       Ni--Cu  Good   8300  0.51   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              V       Ag      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              V       Au      Good   8300  0.51   60000                               (70:30)                                                                       ______________________________________                                    

                  TABLE 1-6                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Mo      Cu      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              Mo      Ni--Cu  Good   8300  0.51   60000                               (70:30)       (70:30)                                                         Ni--Cu                                                                              Mo      Ni--Cu  Good   8300  0.51   60000                               (70:30)       (10:90)                                                         Ni--Cu                                                                              Mo      Ag      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              Mo      Au      Good   8300  0.51   60000                               (70:30)                                                                       Ni--Cu                                                                              Cr      Cu      Good   8250  0.45   70000                               (10:90)                                                                       Ni--Cu                                                                              Cr      Ni--Cu  Good   8250  0.45   70000                               (10:90)       (70:30)                                                         Ni--Cu                                                                              Cr      Ni--Cu  Good   8250  0.45   70000                               (10:90)       (10:90)                                                         Ni--Cu                                                                              Cr      Ag      Good   8250  0.45   70000                               (10:90)                                                                       Ni--Cu                                                                              Cr      Au      Good   8250  0.45   70000                               (10:90)                                                                       Ni--Cu                                                                              Ni--Cr  Cu      Good   8250  0.45   70000                               (10:90)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (90:10) (70:30)                                                         Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (90:10) (10:90)                                                         Ni--Cu                                                                              Ni--Cr  Ag      Good   8250  0.45   70000                               (10:90)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Au      Good   8250  0.45   70000                               (10:90)                                                                             (90:10)                                                                 Ni--Cu                                                                              Ni--Cr  Cu      Good   8250  0.45   70000                               (10:90)                                                                             (20:80)                                                                 Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (20:80) (70:30)                                                         Ni--Cu                                                                              Ni--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (20:80) (10:90)                                                         Ni--Cu                                                                              Ni--Cr  Ag      Good   8250  0.45   70000                               (10:90)                                                                             (20:80)                                                                 ______________________________________                                    

                  TABLE 1-7                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Ni--Cr  Au      Good   8250  0.45   70000                               (10:90)                                                                             (20:80)                                                                 Ni--Cu                                                                              Fe--Cr  Cu      Good   8250  0.45   70000                               (10:90)                                                                             (83:17)                                                                 Ni--Cu                                                                              Fe--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (83:17) (70:30)                                                         Ni--Cu                                                                              Fe--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (83:17) (10:90)                                                         Ni--Cu                                                                              Fe--Cr  Ag      Good   8250  0.45   70000                               (10:90)                                                                             (83:17)                                                                 Ni--Cu                                                                              Fe--Cr  Au      Good   8250  0.45   70000                               (10:90)                                                                             (83:17)                                                                 Ni--Cu                                                                              Co--Cr  Cu      Good   8250  0.45   70000                               (10:90)                                                                             (50:50)                                                                 Ni--Cu                                                                              Co--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (50:50) (70:30)                                                         Ni--Cu                                                                              Co--Cr  Ni--Cu  Good   8250  0.45   70000                               (10:90)                                                                             (50:50) (10:90)                                                         Ni--Cu                                                                              Co--Cr  Ag      Good   8250  0.45   70000                               (10:90)                                                                             (50:50)                                                                 Ni--Cu                                                                              Co--Cr  Au      Good   8250  0.45   70000                               (10:90)                                                                             (50:50)                                                                 Ni--Cu                                                                              Ti      Cu      Good   8250  0.50   70000                               (10:90)                                                                       Ni--Cu                                                                              Ti      Ni--Cu  Good   8250  0.50   70000                               (10:90)       (70:30)                                                         Ni--Cu                                                                              Ti      Ni--Cu  Good   8250  0.50   70000                               (10:90)       (10:90)                                                         Ni--Cu                                                                              Ti      Ag      Good   8250  0.50   70000                               (10:90)                                                                       Ni--Cu                                                                              Ti      Au      Good   8250  0.50   70000                               (10:90)                                                                       Ni--Cu                                                                              Zn      Cu      Good   8250  0.53   70000                               (10:90)                                                                       Ni--Cu                                                                              Zn      Ni--Cu  Good   8250  0.53   70000                               (10:90)       (70:30)                                                         Ni--Cu                                                                              Zn      Ni--Cu  Good   8250  0.53   70000                               (10:90)       (10:90)                                                         ______________________________________                                    

                  TABLE 1-8                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Zn      Ag      Good   8250  0.53   70000                               (10:90)                                                                       Ni--Cu                                                                              Zn      Au      Good   8250  0.53   70000                               (10:90)                                                                       Ni--Cu                                                                              Al      Cu      Good   8250  0.51   70000                               (10:90)                                                                       Ni--Cu                                                                              Al      Ni--Cu  Good   8250  0.51   70000                               (10:90)       (70:30) Good   8250  0.51   70000                               Ni--Cu                                                                              Al      Ni--Cu                                                          (10:90)       (10:90)                                                         Ni--Cu                                                                              Al      Ag      Good   8250  0.51   70000                               (10:90)                                                                       Ni--Cu                                                                              Al      Au      Good   8250  0.51   70000                               (10:90)                                                                       Ni--Cu                                                                              W       Cu      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              W       Ni--Cu  Good   8250  0.49   70000                               (10:90)       (70:30)                                                         Ni--Cu                                                                              W       Ni--Cu  Good   8250  0.49   70000                               (10:90)       (10:90)                                                         Ni--Cu                                                                              W       Ag      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              W       Au      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              V       Cu      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              V       Ni--Cu  Good   8250  0.49   70000                               (10:90)       (70:30)                                                         Ni--Cu                                                                              V       Ni--Cu  Good   8250  0.49   70000                               (10:90)       (10:90)                                                         Ni--Cu                                                                              V       Ag      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              V       Au      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              Mo      Cu      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              Mo      Ni--Cu  Good   8250  0.49   70000                               (10:90)       (70:30)                                                         ______________________________________                                    

                  TABLE 1-9                                                       ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Ni--Cu                                                                              Mo      Ni--Cu  Good   8250  0.49   70000                               (10:90)       (10:90)                                                         Ni--Cu                                                                              Mo      Ag      Good   8250  0.49   70000                               (10:90)                                                                       Ni--Cu                                                                              Mo      Au      Good   8250  0.49   70000                               (10:90)                                                                       Zn    Cr      Cu      Good   8350  0.59   70000                               Zn    Cr      Ni--Cu  Good   8350  0.59   70000                                             (70:30)                                                         Zn    Cr      Ni--Cu  Good   8350  0.59   70000                                             (10:90)                                                         Zn    Cr      Ag      Good   8350  0.59   70000                               Zn    Cr      Au      Good   8350  0.59   70000                               Zn    Ni--Cu  Cu      Good   8350  0.59   70000                                     (10:90)                                                                 Zn    Ni--Cu  Ni--Cu  Good   8350  0.59   70000                                     (10:90) (70:30)                                                         Zn    Ni--Cu  Ni--Cu  Good   8350  0.59   70000                                     (10:90) (10:90)                                                         Zn    Ni--Cu  Ag      Good   8350  0.59   70000                                     (10:90)                                                                 Zn    Ni--Cu  Au      Good   8350  0.59   70000                                     (90:10)                                                                 Zn    Ni--Cr  Cu      Good   8350  0.59   70000                                     (20:80)                                                                 Zn    Ni--Cr  Ni--Cu  Good   8350  0.59   70000                                     (20:80) (70:30)                                                         Zn    Ni--Cr  Ni--Cu  Good   8350  0.59   70000                                     (20:80) (10:90)                                                         Zn    Ni--Cr  Ag      Good   8350  0.59   70000                                     (20:80)                                                                 Zn    Ni--Cr  Au      Good   8350  0.59   70000                                     (20:80)                                                                 Zn    Fe--Cr  Cu      Good   8350  0.59   70000                                     (83:17)                                                                 Zn    Fe--Cr  Ni--Cu  Good   8350  0.59   70000                                     (83:17) (70:30)                                                         ______________________________________                                    

                  TABLE 1-10                                                      ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Zn    Fe--Cr  Ni--Cu  Good   8350  0.59   40000                                     (83:17) (10:90)                                                         Zn    Fe--Cr  Ag      Good   8350  0.59   40000                                     (83:17)                                                                 Zn    Fe--Cr  Au      Good   8350  0.59   40000                                     (83:17)                                                                 Zn    Co--Cr  Cu      Good   8350  0.59   40000                                     (50:50)                                                                 Zn    Co--Cr  Ni--Cu  Good   8350  0.59   40000                                     (50:50) (70:30)                                                         Zn    Co--Cr  Ni--Cu  Good   8350  0.59   40000                                     (50:50) (10:90)                                                         Zn    Co--Cr  Ag      Good   8350  0.59   40000                                     (50:50)                                                                 Zn    Co--Cr  Au      Good   8350  0.59   40000                                     (50:50)                                                                 Zn    Ti      Cu      Good   8350  0.65   40000                               Zn    Ti      Ni--Cu  Good   8350  0.65   40000                                             (70:30)                                                         Zn    Ti      Ni--Cu  Good   8350  0.65   40000                                             (10:90)                                                         Zn    Ti      Ag      Good   8350  0.65   40000                               Zn    Ti      Au      Good   8350  0.65   40000                               Zn    Zn      Cu      Good   8350  0.63   40000                               Zn    Zn      Ni--Cu  Good   8350  0.63   40000                                             (70:30)                                                         Zn    Zn      Ni--Cu  Good   8350  0.63   40000                                             (10:90)                                                         Zn    Zn      Ag      Good   8350  0.63   40000                               Zn    Zn      Au      Good   8350  0.63   40000                               Zn    Al      Cu      Good   8350  0.63   40000                               Zn    Al      Ni--Cu  Good   8350  0.63   40000                                             (70:30)                                                         Zn    Al      Ni--Cu  Good   8350  0.63   40000                                             (10:90)                                                         Zn    Al      Ag      Good   8350  0.63   40000                               Zn    Al      Au      Good   8350  0.63   40000                               Zn    W       Cu      Good   8350  0.63   40000                               ______________________________________                                    

                  TABLE 1-11                                                      ______________________________________                                                               Electrical Characteristic                              Electrode     Wetting                 Insulation                              First Second  Third   Property     Dielectric                                                                           Resistance                          Layer Layer   Layer   of Solder                                                                            ε                                                                           Loss (%)                                                                             (MΩ)                          ______________________________________                                        Zn    W       Ni--Cu  Good   8350  0.63   40000                                             (70:30)                                                         Zn    W       Ni--Cu  Good   8350  0.63   40000                                             (10:90)                                                         Zn    W       Ag      Good   8350  0.63   40000                               Zn    W       Au      Good   8350  0.63   40000                               Zn    V       Cu      Good   8350  0.63   40000                               Zn    V       Ni--Cu  Good   8350  0.63   40000                                             (70:30)                                                         Zn    V       Ni--Cu  Good   8350  0.63   40000                                             (10:90)                                                         Zn    V       Ag      Good   8350  0.63   40000                               Zn    V       Au      Good   8350  0.63   40000                               Zn    Mo      Cu      Good   8350  0.63   40000                               Zn    Mo      Ni--Cu  Good   8350  0.63   40000                                             (70:30)                                                         Zn    Mo      Ni--Cu  Good   8350  0.63   40000                                             (10:90)                                                         Zn    Mo      Ag      Good   8350  0.63   40000                               Zn    Mo      Au      Good   8350  0.63   40000                               ______________________________________                                    

As is understood from the tables, the electrodes 5a and 5b have a goodsoldering performance, and have excellent values of the dielectricconstant ε, dielectric loss and insulation resistance so that the effectof the present invention is significant.

As is clear by the above description and in accordance with the presentinvention, since the dry plated electrode on the surface of the ceramicelement assembly is structured by a first layer made of any one or moreof Cu, Ni--Cu alloy and Zn, a second layer provided on a surface of thefirst layer and made of a material different from the material of thefirst layer and further any one or more of Cr, Ni--Cr alloy, Fe--Cralloy, Co--Cr alloy, Ti, Zn, Al, W, V and Mo, and a third layer providedon a surface of the second layer and made of any one or more of Cu,Ni--Cu alloy, Ag and Au, a ceramic capacitor having improved electrodesoldering performance, little or no diffusion of solder even under ahigh temperature environment and a reduced characteristic deteriorationcan be obtained.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.

What is claimed is:
 1. A ceramic capacitor comprising:a ceramic elementassembly and a capacitance obtaining dry plated electrode on a surfaceof the ceramic element assembly; wherein said dry plated electrode has afirst layer of at least one member selected from the group consisting ofCu, Ni--Cu alloy and Zn, a second layer on a surface of the first layerand of a material different from the material of said first layer andbeing at least one material selected from the group consisting of Cr,Ni--Cr alloy, Fe--Cr alloy, Co--Cr alloy, Ti, Zn, Al, W, V and Mo, and athird layer on a surface of the second layer and being at least onematerial selected from the group consisting of Cu, Ni--Cu alloy, Ag andAu.
 2. A ceramic capacitor as recited in claim 1, wherein said firstlayer has a thickness of at least about 500 angstroms or more, saidsecond layer has a thickness of at least about 100 angstroms or more andsaid third layer has a thickness of at least about 500 angstroms ormore.
 3. A ceramic capacitor as recited in claim 2, wherein said firstlayer is Cu.
 4. A ceramic capacitor as recited in claim 2, wherein saidfirst layer is Ni--Cu alloy.
 5. A ceramic capacitor as recited in claim2, wherein said first layer is Zn.
 6. A ceramic capacitor as recited inclaim 1, wherein said first layer is Cu.
 7. A ceramic capacitor asrecited in claim 1, wherein said first layer is Ni--Cu alloy.
 8. Aceramic capacitor as recited in claim 1, wherein said first layer is Zn.